This invention pertains generally to electron guns and more particularly to an electron gun which is particularly suitable for use in an Auger spectrometer.
In Auger analysis, where an electron beam is directed at a sample to be analyzed, it is essential that the beam be sharp and well defined to provide high resolution and freedom from distortion. Toward this end, it is desirable that the final lens in the gun producing the beam be positioned as close to the sample as possible.
Electron guns generally include deflection plates for deflecting the beam to effect scanning of the sample and some means for correcting astigmatism in the beam. In the guns of the prior art, the deflection plates and astigmatism corrector are commonly located between the final lens and the sample, and they prevent the lens from being positioned as close to the sample as would otherwise be desirable.